What Is SPF and How Does It Protect You?
By Emil Kristensen CMO
@ Sleeknote

If you spend any amount of time outdoors, you are likely familiar with the term SPF. But what exactly is it, and why is it so important? Sun protection factor, or SPF, is a measure of how well a sunscreen can protect your skin from harmful UV radiation. In this article, we will explore the science behind SPF and why it is vital for your skin’s health.

The Science Behind SPF: Understanding Ultraviolet Radiation

Before we dive into SPF, it’s essential to understand the different types of ultraviolet radiation (UV) and their effects on your skin. There are two types of UV rays that reach the earth’s surface: UVA and UVB. UVA rays penetrate the skin more deeply than UVB rays and are responsible for premature ageing and skin damage. UVB rays are the primary cause of sunburn and skin cancer.

It’s important to note that UV rays can still penetrate through clouds and windows, meaning that even on cloudy days or when indoors, your skin is still at risk of damage. Additionally, UV rays are strongest during midday, so it’s crucial to take extra precautions during this time, such as seeking shade or wearing protective clothing.

Different Types of UV Rays and Their Effects on Your Skin

UV rays can cause a range of skin-related problems, including wrinkles, pigmentation, and skin cancer. UVA and UVB rays penetrate the skin differently and cause distinct forms of skin damage. UVA rays can lead to skin pigmentation and damage to elastin fibers, the protein responsible for skin’s elasticity. In contrast, UVB rays can damage the skin’s surface layer and cause sunburn and skin cancer.

It is important to note that there is a third type of UV ray, known as UVC, which is the most harmful but is typically absorbed by the Earth’s atmosphere before reaching the surface. However, with the depletion of the ozone layer, UVC rays may become a greater concern in the future. It is crucial to protect your skin from all types of UV rays by wearing sunscreen, protective clothing, and avoiding prolonged exposure to the sun during peak hours.

SPF Ratings Explained: What Do the Numbers Mean?

SPF measures how well a sunscreen protects your skin from UVB rays and, to some extent, UVA rays. The number on the label refers to the sunscreen’s ability to prevent UVB rays from damaging your skin. For example, an SPF 30 sunscreen will block approximately 97% of UVB rays, while an SPF 50 sunscreen will block around 98% of UVB rays. Higher SPF doesn’t mean you can stay out in the sun for longer. Rather, it means a sunscreen with a higher SPF provides greater protection against UVB rays.

It’s important to note that SPF only measures protection against UVB rays, which are the primary cause of sunburn and skin cancer. UVA rays, on the other hand, penetrate deeper into the skin and can cause long-term damage such as premature aging and skin cancer. To ensure full protection, it’s recommended to use a broad-spectrum sunscreen that protects against both UVA and UVB rays. Look for sunscreens that contain ingredients such as zinc oxide, titanium dioxide, avobenzone, or Mexoryl SX, which provide broad-spectrum protection.

Choosing the Right SPF for Your Skin Type and Needs

When selecting a sunscreen, it’s important to know your skin type and the intensity of UV radiation in your environment. People with fair skin who burn easily or have a history of skin cancer should use a sunscreen with a higher SPF. Sunscreen should be reapplied every two hours, regardless of the SPF. For individuals with sensitive skin, it’s essential to choose a mineral-based sunscreen that contains titanium dioxide or zinc oxide and is free of fragrances and chemicals.

Sunscreen Application Tips for Maximum Protection

Proper application is critical for sunscreen to be effective. Apply sunscreen 15-30 minutes before going outside, ensuring you apply it on all exposed areas, including the ears and back of the neck. Don’t forget to apply sunscreen to your lips, using a lip balm with an SPF of at least 30. Apply a generous amount of sunscreen – about a shot glass full for the body and a nickel-sized dollop for the face. Reapply every two hours, or immediately after swimming or sweating profusely.

The Importance of Reapplying Sunscreen Throughout the Day

Reapplying sunscreen every two hours is crucial for maximum protection from UV radiation. Even if you’re indoors, UVA rays penetrate windows, so it’s essential to apply sunscreen if you’re sitting near a window. If you’re swimming or sweating, you should reapply immediately to ensure you’re adequately protected.

Sun Protection Beyond Sunscreen: Clothing, Hats, and Shade

Sunscreen alone may not be enough to protect your skin from UV rays. Wearing protective clothing, hats, and sunglasses can also reduce sun damage and skin cancer risk. Choose clothing with a UPF (Ultraviolet Protection Factor) rating that blocks UV radiation and wears a wide-brimmed hat to protect your face and neck.

Common Myths About SPF and Sun Protection Debunked

Myths about sun protection abound. One common misbelief is that sunscreen is a one-time application that will last all day. As we learned above, sunscreen should be reapplied every two hours. Another myth is that you don’t need sunscreen on cold or overcast days when, in fact, UV radiation is present in these conditions. Finally, choosing a sunscreen with an SPF of 100 provides little additional protection compared to an SPF 50 sunscreen.

The Consequences of Not Using SPF: Skin Damage and Skin Cancer Risk

Skipping sunscreen or not wearing adequate sun protection can lead to a range of skin damage, from premature ageing to an increased risk of skin cancer. Skin cancer is the most common type of cancer in the US, and UV radiation is the leading cause of skin cancer. Protecting your skin from the sun with sunscreen and protective clothing is vital to maintaining skin health and preventing skin cancer.

In conclusion, SPF is an essential component of sun protection. Knowing how it works, selecting the right one for your skin, and applying it correctly can go a long way in preventing skin damage and skin cancer. Remember to apply sunscreen every two hours and choose protective clothing when possible to keep your skin healthy and safe from UV radiation.